Isovolemic hemodilution and pancreatic islet blood flow in the rat

Adult rats were isovolemically hemodiluted with isotonic dextran-solutions to reduce the hematocrit by approximately one third. This procedure decreased the mean arterial blood pressure but markedly increased cardiac output. The serum glucose concentration was increased, whilst the serum insulin concentration remained unchanged. The blood flow values and the vascular conductances of both the whole pancreas and the islets were reduced by 40-60% by hemodilution. However, the decrease in islet blood flow was less affected as indicated by the increase in the percentage fraction of whole pancreatic blood flow diverted through the islets (13.5 +/- 0.7% compared to 9.7 +/- 0.8%; p < 0.05). It is concluded that isovolemic hemodilution, despite a markedly increased cardiac output, decreased both whole pancreatic blood flow and islet blood flow.